Robert MacNeil writes in today’s Washington Post that the presumptive power and influence of Walter Cronkite, the former CBS News anchorman, “has morphed into a general civic belief.”

Let’s hope not.

Let’s hope the opposite effect is becoming more pronounced — that Cronkite’s presumed influence is slowly being recognized for the myth that it is.

MacNeil, the former co-anchor of the PBS News Hour program, takes up the notion of Cronkite’s power to move national events in a review of the Cronkite biography that came out at the end of May.

The biography, written by Douglas Brinkley and titled Cronkite, appeared for a short time on the New York Timeslist of non-fiction best-sellers. I found the book hagiographic, especially its treatment of the so-called “Cronkite Moment” of late February 1968.

That was when Cronkite declared on the air that the U.S. military was “mired in stalemate” in Vietnam and suggested that negotiations might lead to a way out.

But as I pointed out in my 2010 book, Getting It Wrong, Cronkite’s “stalemate” characterization was hardly novel and exerted little demonstrable effect on the policy or decisions of the administration of President Lyndon B. Johnson. The myth also has it that Cronkite’s “mired in stalemate” commentary prompted Johnson not to seek reelection in 1968.

MacNeil in his review notes the doubts about whether Cronkite’s assessment exerted much influence on Johnson but asserts nonetheless the “idea [that it did] has morphed into a general civic belief.”

It’s regrettable that MacNeil didn’t pause to consider the implications of the morphing, or reflect on why the myth of the “Cronkite Moment” is so appealing and so eagerly retold, despite the considerable evidence that can be arrayed in debunking it.

Cronkite himself (until late in his life) rejected the notion that his “mired in stalemate” assessment was all that influential, likening the effect to that merely of a “straw on the back of a crippled camel.”

Indeed, other news organizations in February 1968 were offering assessments far more pointed that Cronkite’s. For example, the Wall Street Journal said a few days before Cronkite’s “mired in stalemate” commentary that the U.S. war effort in Vietnam “may be doomed.”

National political figures likewise were expressing downbeat opinions about the war that month. George Romney, then a long-shot Republican candidate for president, declared in mid-February 1968: